For the purpose of plating small pieces of materials, the barrel plating technology has been used. In this plating process, a bunch of small pieces of materials is put in a plating barrel (that is a barrel shape container or a cylindrical shape container) and the barrel is immersed in the plating liquid in order to plate the small pieces of materials (for example, see the reference 1). In order to keep the plating liquid comes in and goes out from the plating barrel without intrusion, many holes or slits are made in the surrounding surface of the plating barrel. The size and the shape of the holes (including slits and meshes) should be designed in such a way that no pieces of the material to be plated fall out from the plating barrel.
Reference 1:
Japanese Published Patent, 2002-241997, A (2002)
In the conventional technologies, mechanical drill machines and drill lasers are used to make the holes, slits or meshes in proper control of physical sizes thereof. However the minimum sizes of the holes, slits and meshes by such mechanical means are limited by the order of 0.1 mm and are not possible down to 0.001 mm. This is true even in the case when the plating barrel is made of metal wire cloth.
For the piece parts plating, small sizes of holes, slits or meshes for the plating barrels are required since the sizes of piece parts become smaller and smaller in the advance of technologies. The larger size of the holes, slits or meshes of the plating barrels cannot hold the piece parts in the barrel plating process. The mechanical process to make holes, slits or meshes takes long time and results in high cost fabrication.